Low foaming nonionic detergents



United States Patent 3,539,519 LOW FOAMING NONIONIC DETERGENTS Dean R.Weimer, Ponca City, Okla, assignor to Continental Oil Company, PoncaCity, Okla, a corporation of Delaware Continuation-impart of abandonedapplication Ser. No. 707,401, Feb. 23, 1968. This application Feb. 14,1969, Ser. No. 799,519

Int. Cl. Clld 1/72 US. Cl. 252-89 6 Claims ABSTRACT OF THE DISCLOSURE Ahigh foaming monionic surfactant in the form of an alkylpolyethoxyethanol is further condensed with butylene oxide to provide alow foaming modification thereof having the general formula R(O*CH CH(OC I-I ),,OH.

CROSS REFERENCE TO RELATED APPLICATION This application is acontinuation-in-part of pending application entitled Low FoamingNonionic Detergents," UJS. Ser. No. 707,401, filed Feb. 23, 1968 by DeanR. Weimer now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to a low foaming nonionic detergent composition consistingessentially of a mixture of surface active compounds serially containinga hydrophobic alkyl group, a hydrophilic polyoxyethylene segment and aterminal hydroxy butoxy group.

Description of the prior art -An important class of nonionic detergentis exemplified by those compositions, generally designated ethoxylates,which are obtained by condensing a hydrophobic compound having areplaceable hydrogen atom with a plurality of moles of ethylene oxide.Particularly suitable compounds providing the hydrophobic portion ofsuch ethoxylates are either the higher aliphatic monoalcohols or analkyl substituted phenol. These nonionic compositions are excellentdetergents and are characterized as high foamers in that they are proneto result in profuse sudsing in any cleaning operation involving highlyturbulent agitation conditions. In some industrial and in many householdcleaning applications of the aforesaid type, it is very desirable tomaintain a low level of foam during the cleansing or treating operation.For example, in various household cleaning operations conducted inmechanical washers excessive foaming of the nonionic detergent isobjectionable because the foam interferes with proper rinsing and insome cases impairs cleansing efficiency. Furthermore, high foamingdetergents are ultimately apt to give rise to mechanical difliculties.It is well know in the syndet art that the wetting and/or detergencypower of a surface active agent is not necessarily synonymous with itsfoaming ability. Consequently, considerable investigation has hithertobeen directed toward providing modifications of high foaming nonionicdetergents Whereby the inherent tendency to foam is abated withoutsignificantly detracting from the detergency power exhibited by theunmodified nonionic.

The nonionics with which this invention is concerned are basically achemostructural combination of a hydrophobic group and a segment ofhydrophilic units as can be perceived from the foregoing discussion. Ithas been proposed to terminate the hydrophilic portion with a radicalhaving somewhat lesser hydrophilic characteristics in order to provide alower foaming but equally effective Patented Nov. 10, 1970 modificationthereof from the standpoint of detergency. This has been generallyaccomplished heretofore by further condensing the ethoxylate withpropylene oxide to provide a terminal polyoxypropylene segment. Thedisadvantage of this approach is twofold in nature. For one, thehydrophobic radical of such modified compositions must be relatively lowin molecular weight thereby necessitating the use of an alcohol whichdoes not yield optimum detergency characteristics. Secondly, if thepreferred higher molecular weight alcohols or alkyl substituted phenolsare utilized to prepare such modified nonionics, the terminalpolyoxypropylene segment must be undesirably large. Too large a terminalsegment of this type poses problems not only in regard tobiodegradability but also has an adverse effect with respect to avariety of more subtle aspects.

OBJECT OF THE INVENTION The primary objective of this invention is toprovide a modified nonionic detergent composition of the alcoholethoxylate type exhibiting low foaming characteristics in combinationwith good biodegradability, Water solubility and physical appearanceproperties.

SUMMARY OF THE INVENTION The present invention is directed to nonionicdetergent compositions comprising a mixture of surface active compoundscorresponding to the following general formula:

where R is a C C alkyl group, and it indicates a range of integersrepresenting the statistical distribution of oxyethylene units obtainedby condensing from about 3.5 to 10 moles of ethylene oxide with a [moleof the compound providing said hydrocarbon groups, namely, a higheraliphatic monoalcohol, and x indicates a range of integers of from about0.5 to 1.5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compounds havingreplaceable hydrogen atoms useful to prepare the base ethoxylates ofthis invention are the various detergent grade aliphatic mono-alcohols.The term aliphatic monoalcohols as used in this disclosure pertains tothose monoalcohols whose carbon atoms are arranged in chains only. Suchalcohols include linear and branched primary and secondary monoalcohols.How ever, the linear alcohols, are more biodegradable. Therefore, thepreferred monoalcohols are the linear alcohols such as exemplified bythe primary alcohols obtained in accordance with the Ziegler synthesismethod or the secondary alcohols prepared by the OX0 process.Particularly desirable alcohols are the linear primary alcohols. Broadlyinclusive of the latter, as well as the linear secondary alcohols, arethose containing from 8 to 18 carbon atoms. Especially useful alcoholswithin this range are the C 4) alcohols and mixture thereof. For thepurpose of making low foaming nonionic detergents for householdcleaninng applications, n-decanol or mixture thereof With minor amountsof dodecanol and/ or tetradecanol provide surface active substanceshaving an optimum balance of properties.

Ethoxylates of the foregoing compounds containing a replaceable hydrogenatom can be prepared by conventional methods. Either acid or basecatalysis is applicable. Base catalysis, however, is preferred ineffecting the condensation of ethylene oxide with the alcohol. Exemplaryof suitable bases are the alkali metal hydroxides such as LiOH, KOH andNaOH. Sodium hydroxide is the preferred base catalyst for effectingcondensation. Exemplary of suitable acid catalysts are SbCl SnCl, and BFBoron trifluoride is the preferred acid catalyst for effectingcondensation.

The general procedure for carrying out the condensation reactioninvolves adding the requisite amount of ethylene oxide to the alcoholtogether with the catalyst selected and heating the reactants to anelevated temperature under autogenous pressure. The ethoxylation orcondensation reaction can be carried out in a temperature range of fromabout 320 to 380 F. The preferred temperature range is from about 340 to360 F. The foregoing temperature ranges are applicable for the preferredcatalyst, specifically sodium hydroxide. When using an acid catalyst,such as boron trifiuoride, a lower temperature is to be observed. Arange of from about 175 to 220 F. is suitable for such catalysis.

The amount of ethylene oxide to be reacted with the monoalcohol isprimarily dependent upon the molecular weight of said alcohol. As themolecular weight of the hydrophobe portion increases, the use ofcorrespondingly greater amounts of ethylene oxide is the customarypractice. 'For the broad range of alcohols contemplated herein thecorresponding amount of ethylene oxide ranges from about 3.5 to 10 molesper mole of the alcohol. An ethylene oxide range of from 3.5 to 6 molesper mole of the preferred C to C alcohols is applicable. However, inorder to produce a nonionic low foaming composition having excellentsolubility properties I prefer to employ from about 5.2 to 5.7 moles ofethylene oxide per mole of the C to C alcohols or blends thereof.Desirable results have also been obtained where the resultant condensateis the reaction product of a mole of a C -C alcohol and from about to 6moles of ethylene oxide. The preferred weight ratio of ethylene oxide toany given alcohol in the resultant condensate is in the To furtherillustrate the best manner contemplated for carrying out the inventionthe following working examples are set forth. As indicated, the examplesare primarily given by way of illustration, and accordingly anyenumeration of details set forth therein are not to be interpreted as alimitation on the invention except as such limitations are indicated inthe appended claims. All parts are parts by weight unless otherwisestated.

EXAMPLE I A series of butylene oxide capped alcohol ethoxylates wasprepared following the general procedure of reacting ethylene oxide withthe alcohol at about 350-360 F. in the presence of NaOH catalyst in theamount of about 0.125 percent based on the weight of the alcohol.Capping of the resultant ethoxylates was accomplished in those runsemploying base catalysis by adding the requisite amount of 1,2-butyleneoxide and heating at approximately the temperature observed in effectingethoxylation. In the run in which capping with the butylene oxide wasconducted in the presence of BF catalyst (about 0.1 percent based on theweight of the ethoxylate) the crude ethoxylate product was firstneutralized with glacial acetic acid and then filtered. All of thecapped products were then heated at from 340 to 360 F. and at about 10mm. Hg to remove any light ends contained by the product. Followingremoval of the light ends, the products were neutralized and filtered.Details as to the respective compositions of these runs as well as theircomparative performance in several loW foam testing methods and theirwetting ability as determined by the standard Draves test are given inthe following Table 1. Also indicated in the table is the generalresistance of the various products to biological assimilation in astandorder of from 1.3 to 1.8. Especially when using a monoardbiodegradation test.

TABLE 1 Moles Low foam tests Percent Moles BO per Wetting E0 in E0 inmole of Num Num- Nom- Numtest Biodegrad- Primary alcohol or mixtureethoxylate ethoxylate ethoxylate her 1 her 2 her 3 bar 4 No. 5 ability85% Clo-8% C12"7% C14 58 5. 2 0 2. 8 2.0 0.9 1. 3 6.3 Good. 2. 85%Clo-8% Gig-7% C 3. 7 l 1 0. 6 0.6 0. 4 0. 6 D0. 3. 85% C o-8% G g-7% C59 5. 5 1 1.2 0. 4 0.3 0.7 7. 2 Do. 4. 85% Clo-8% (Em-7% C 60 5. 7 1 1.20. 5 0.3 0. 8 7.0 Do. 5.-. 85% Clo-8% Cir-7% C 61 6. 0 1 1.7 0. 5 O. 50.7 6. 2 D0. 6 85% C o-8% Gig-7% CM 58 5. 2 1 1 1. 6 0. 4 0. 3 0.8 9.2Do.

1 BEE) used as catalyst for capping.

alcohol, the aforesaid range of ethylene oxide provides about theoptimum balance of properties for the resultant condensate.

In accordance with this invention the ethoxylates described hereinaboveare then reacted with butylene oxide in a manner whereby a substantialportion of the ethoxylated compounds are terminated with a hydroxybutoxy grouping. An applicable amount of butylene oxide for achievingsuch capping is from 0.5 to 1.5 moles of butylene oxide per mole of theethoxylate. The preferred compositions are those obtained by condensingthe ethoxylated product with about 0.75 to 1.25 moles of butylene oxide.Especially desirable results have been obtained wherein the ethoxylatedproduct is condensed with about 1 mole of butylene oxide. Again, eitherbase or acid catalysis can be used to achieve capping of the ethoxylate.A- base such as sodium hydroxide is preferred from the standpoint ofconvenient processing. However, the use of an acid catalyst such asboron trifiuoride for this purpose results in a product having somewhatbetter physical appearance than those capped materials prepared usingbase catalysis for the capping step. The respective ranges oftemperatures, including the preferred ranges discussed hereinabove inconnection with preparing the ethoxylate, are precisely applicable inachieving A summary of the various test methods used are as follows:

Test No. 1.0.1% surfactant in 200 ml. aqueous solution. Stirred on maltmixer at high speed at 75 F. for 3 minutes. Solution allowed to stand 2minutes and the foam height measured in centimeters.

Test No. 2.Same as No. 1 except that test is run at F.

Test No. 3.0.006% surfactants and 0.194 sodium silicate in 200 ml.aqueous solution. Stirred on malt mixer at high speed and 140 F. for 3minutes. Solution allowed to stand 45 seconds and foam height measuredin centimeters.

Test No. 4.0.006% surfactant, 0.194% sodium silicate and 0.1% powderedmilk in 200 ml. aqueous solution. Test procedure is the same as Test No.3. Tests 3 and 4 measure the defoaming ability of the surfacant for usewhere proteinaceous material is present.

Test No. 5.Measures wetting time of 0.1% solution of the surfactant at75 F. A 5 gm. Draves cotton skein and a 3 gm. hook used.

The above data clearly indicates that a nonionic compound having thegeneral formula R(OCH CH (OC H OH where R is a linear a-lkyl radicalhaving 10 to 14 carbon atoms, n is an integer 3.7 to 6.0 and x is 1possesses excellent cotton wetting properties and good biodegradableproperties. The data further illustrates that by incorporating 1 mole ofbutylene oxide into a high foam nonionic, such as in Run No. 1, theresulting nonionic compound possesses desired low foam propertieswithout sacrificing the above-mentioned desirable properties.

EXAMPLE II A series of propylene oxide capped ethoxylates was preparedfollowing the general procedure outlined in Example I except thatpropylene oxide was substituted for the 1,2-butylene oxide. Details asto the respective compositions of these runs as well as theircomparative performance in several low foam testing methods and theirWetting ability as determined by the standard Draves test are given inthe following Table 2.

R(OCH CH (OC H OH wherein R is a C to C alkyl group, n is an integer ofTABLE 2 Percent E Moles E O Moles P0 Low foam tests Wetting in 1n pertest Biodegrad- Run Primary alcohol or mixture ethoxylate ethoxylatemole of N0. 1 N o. 2 No. 3 ability ethoxylate 6 45% 08-55% Cw 60 5 0.5 016.7 Poor. 7 85% C1u-3% C12-7% C14..- 73 10. 4 0 5. 2 4. 1 24.0 Good. 885% G n-8% C12 7% C14 78 10.4 1 4.5 2.7 19.2 Fair. 9 40% -30% e -20%Ora-10% c 62.5 8.1 0 4.0 3.1 Good.

40% (hr-30% C Gu -10% C13..- 65 9 3. 5 3. l 1. 6 P001.

(In- C14"20% C1e* C18"- 66 9. 5 7 3. 3 0. 6 D0.

Summary of the various test methods used are as from about 3.5 to 10 andx is an integer from about 0.5 follows: to 1.5.

Test No. 1.O.1% surfactant in 200 ml. aqueous solu- 2. The compositionsof claim 1 wherein x is from 0.75 tion. Stirred on malt mixer at highspeed at 75 F. for 3 to 1.25. minutes. Solution allowed to stand 2minutes and the 30 3. The compositions according to claim 1 wherein foamheight measured in centimeters. x is about 1.

Test No. 2.Same as No. 1 except the test is run at 4. The compositionsaccording to claim 3 wherein 140 F. R is a C to C linear group and n isfrom about 3.5

Test No. 3.Measures wetting time of 0.1% solution to 6. of thesurfactant at 75 F. A 5 gm. Draves cotton skein 5. The compositionsaccording to claim 4 wherein n and a 3 gm. hook used. is about 5.2 to5.7.

Referring to the above data Run NO. 8, When C m- 6. The compositionsaccording to claim 3 wherein R pared with Run No. 7, illustrates thatwhen 1 mole of is a C to C linear group and n is from about 5 to 6.propylene oxide is employed to cap the original ethoxylate the smalldecrease in foam of the propylene Exide References Ci capped nonionic isnot sufficient to make it a 0W oam nonionic. In order to get gooddefoaming properties the UNITED STATES PATENTS propylene oxide ratio tothe ethoxylate must be relatively 2,671,115 3 1954 KOSmlIl. high. Thisis illustrated in Runs No. 6 and 11 where the 2,370,220 /1959 Carter.ratio of ethylene oxide to propylene oxide is approxi- 2,903,486 9/ 1959Brown et al. mately 1:1. However, the nonionics containing an effec-2,965,678 12/1960 Jllfldbelg et a1- tive amount of propylene oxideexhibit poor biodegrad- 3,101,374 8/1963 i ability. The data alsoillustrates that the wetting speed 3 3 9/ 1967 Welbertof the propyleneoxide capped nonionic is substantially FOREIGN PATENTS poorer than thebutylene oxlde capped llOl'llOIllC of Example I- 538,843 3/1957 Canada.

Therefore, when comparing the results of Table I and Table II, i.e.,butylene oxide capped nonionic and pro- LEON D. ROSDOL, Pflmary Examlnelpylene oxide capped nonionic, one can readily see that the butyleneoxide capped nonionic produces superior SCHULZ Assistant Examinerresults. Further, the butylene oxide capped nonionic has Us Cl X R amuch lower ratio of butylene oxide to ethylene oxide than the propyleneoxide to ethylene oxide ratio in the 615 propylene oxide cappednonionic.

The foregoing discussion and description has been

